The objective of this proposal is to complete the engineering development and testing of the Non-Invasive Self- calibrating Ambulatory Multi-Modality (NISAM) blood pressure device to recognize hypertensive patients not currently identified using today's technology. As well as providing better management of hypertensive patients by presenting a truer round-the-clock picture of their blood pressure (BP) variation. Hypertension is increasing worldwide and represents an annual burden of $47.5 billion in healthcare costs and resources in addition to $3.5 billion yearly in lost productivity. In the U.S. 80 million people have hypertension, though only 80% are aware of their condition, and only 48% have it adequately controlled. As with every disease state, proper measurement of the problem is required. Patient BP varies throughout the day, week and year. Existing in- clinic BP measurements are infrequent and prone to errors. The NISAM device combines four different sensor technologies into a wearable wireless non-invasive BP measurement device that does not require an inflation cuff. The device is worn over the patient's brachial artery near the elbow At only 3 cm x 3 cm it is small, unobtrusive and easy to use. The device monitors patient movement and uses this information to assess when to collect data. It can store months and up to years of data and wirelessly transmit this to a smart phone or to a hospital's electronic medical records system. The NISAM device's clinical benefits include: an unobtrusive BP measurement system to identify hypertensive patients not currently recognized using today's methods, as well as better managing existing hypertensive patients by understanding their true BP variation. Also, the NISAM device will display the BP data to support clinically actionable decisions through patient-specific, efficient and easy to understand diagnostic reports. In addition, patient compliance is greatly improved because this device does not require an inflation cuff, which is disruptive to patient's sleep. In this Phase I proposal we will demonstrat feasibility and complete engineering development and testing of the NISAM BP sensors and actuator system, and compare measurements with a standard clinical BP cuff in bench/mock and human testing. To achieve this objective a mock artery setup will be used to demonstrate performance and accuracy using the force actuator and four different sensor techniques. Also, prototypes will be built to measure the accuracy of the four sensors on human subjects and compare results to inflation cuff systems. The long-term goal is to clinically utilize the NISAM device to better identify and manage hypertensive patients, using a small, wearable, wireless easy to use BP device.